AceShowbiz - Prince Charles has described slavery as an "appalling atrocity" and something "which forever stains our history."

The British royal - who was speaking during the ceremony marking Barbados' transition to a republic - opened up on the period of the U.K.'s past as its "darkest days" while insisting the "creation of this republic offers a new beginning."

In front of guests including Rihanna, who was named an ambassador for her home country three years ago, and prime minister Mia Mottley, Charles said, "The creation of this Republic offers a new beginning, but it also marks a point on a continuum, a milestone on the long road you have not only travelled, but which you have built."

"From the darkest days of our past, and the appalling atrocity of slavery, which forever stains our history, the people of this island forged their path with extraordinary fortitude."

"Emancipation, self-government and Independence were your way-points. Freedom, justice and self-determination have been your guides."

"Your long journey has brought you to this moment, not as your destination, but as a vantage point from which to survey a new horizon."

The country's first president - Dame Sandra Mason - has been sworn into office, and she has replaced Queen Elizabeth as head of state, which is a role she had held since it became independent in 1966.

In a message to both the president and the people of Barbados, the Queen sent them her "warmest good wishes for your happiness, peace and prosperity in the future."

She added that the country has a "special place" in her heart due to "its vibrant culture, its sporting prowess, and its natural beauty."

She added her happiness that the nation is staying as part of the Commonwealth while U.K. prime minister Boris Johnson said the two country's will stay "steadfast friends and allies" with "a partnership built to last."